For prompting a user to practice environmentally friendly driving, an example system evaluates user's driving situations and notifies the user of an evaluation result (e.g., see patent document 1).                Patent document: JP-2002-104023A (US2002/0062191 A1)        
This type of system for prompting the user to do environmentally friendly driving determines simply whether or not an engine is idle. For instance, the system notifies the user of such information that the engine is idling too long. When the system only determines whether or not the engine is idling, the user can be simply notified of this information but cannot be easily notified whether or not the user is responsible for the idling state. For example, the user may not be able to easily prevent an idling state, for which the user is not directly responsible, when the engine is idling because his or her vehicle waits for the traffic light to change at an intersection or temporarily stops due to traffic congestion. In contrast, the user may be able to stop an idling state, for which the user is directly responsible, when the engine is idling uselessly. Accordingly, the above system does not allow the user to be fully conscious of environmentally friendly driving.